from fastapi.testclient import TestClient
from sqlalchemy import create_engine
from sqlalchemy.orm import Session
from sqlalchemy.pool import StaticPool

from central.app import api as api_module
from central.app.main import create_app
from central.app.models import Base

HEADERS = {"Authorization": "Bearer test-token"}
PAYLOAD = {"current_ncm": "22030000", "description": "CERVEJA LATA"}


def make_client(monkeypatch, calls, engine_version="0.3.0", datasets=None):
    versions = datasets if datasets is not None else {"ncm": "aaa"}

    class FakeClassifier:
        def __init__(self, repository): pass

        def classify(self, product):
            calls.append(product)
            return {"status": "EXACT_NCM", "engine_version": api_module.ENGINE_VERSION, "decision_version": "x", "dataset_versions": dict(versions), "classification": {"ncm": product["current_ncm"]}}

    monkeypatch.setattr(api_module, "Classifier", FakeClassifier)
    monkeypatch.setattr(api_module, "ENGINE_VERSION", engine_version)
    monkeypatch.setattr(api_module.DatasetService, "dataset_versions", lambda self: dict(versions))
    engine = create_engine("sqlite://", connect_args={"check_same_thread": False}, poolclass=StaticPool)
    Base.metadata.create_all(engine)
    return TestClient(create_app(session_factory=lambda: Session(engine), bootstrap_token="test-token")), versions


def test_cache_hit_does_not_run_the_classifier(monkeypatch):
    calls = []
    client, _ = make_client(monkeypatch, calls)
    first = client.post("/v1/classify", json=PAYLOAD, headers=HEADERS).json()
    assert first["provenance"]["cache_hit"] is False and len(calls) == 1
    for _ in range(3):
        again = client.post("/v1/classify", json=PAYLOAD, headers=HEADERS).json()
        assert again["provenance"]["cache_hit"] is True
        assert {k: v for k, v in again.items() if k != "provenance"} == {k: v for k, v in first.items() if k != "provenance"}  # same fiscal result
    assert len(calls) == 1  # CLASSIFIER_EXECUTIONS_ON_HIT = 0


def test_batch_hits_skip_the_classifier_and_new_inputs_miss(monkeypatch):
    calls = []
    client, _ = make_client(monkeypatch, calls)
    products = [PAYLOAD, {"current_ncm": "19022000", "description": "MASSA"}]
    client.post("/v1/classify/batch", json={"products": products}, headers=HEADERS)
    assert len(calls) == 2
    res = client.post("/v1/classify/batch", json={"products": products + [{"current_ncm": "20099000", "description": "SUCO"}]}, headers=HEADERS).json()["results"]
    assert [r["provenance"]["cache_hit"] for r in res] == [True, True, False] and len(calls) == 3


def test_engine_or_dataset_version_change_invalidates_naturally(monkeypatch):
    calls = []
    client, versions = make_client(monkeypatch, calls)
    client.post("/v1/classify", json=PAYLOAD, headers=HEADERS)
    versions["ncm"] = "bbb"  # a new ACTIVE dataset version changes dataset_versions()
    assert client.post("/v1/classify", json=PAYLOAD, headers=HEADERS).json()["provenance"]["cache_hit"] is False
    monkeypatch.setattr(api_module, "ENGINE_VERSION", "0.4.0")
    assert client.post("/v1/classify", json=PAYLOAD, headers=HEADERS).json()["provenance"]["cache_hit"] is False
    assert len(calls) == 3